In the periphery of a vehicle, there is a blind spot not visible from the position of a driver. Hence, the driver needs to pay great attention to the periphery of the vehicle during driving of the vehicle. In particular, when the vehicle is to be parked by reversing, many users have awareness of not being good at parking operations per se, so they suffer from mental fatigue to no small extent. Then, conventionally, there has been taken advantage of a technique of monitoring an obstacle in the periphery of a vehicle (e.g. Patent Documents 1 and 2).
An obstacle alert device for a vehicle disclosed in Patent Document 1 includes a transversely moving obstacle detecting means, a transverse movement direction detecting means, and a transverse movement information providing means. The transversely moving obstacle detecting means detects an obstacle which is moving in a direction transverse to the traveling direction in front of the vehicle. The transverse movement direction detecting means detects the transverse movement direction of the obstacle detected by the transversely moving obstacle detecting means. The transverse movement information providing means provides the driver with information relating to the transverse movement direction of the obstacle detected by the transverse movement direction detecting means. In this, the transverse movement information providing means causes a display unit to display in its monitoring screen an arrow representing the transverse movement direction detected by the transverse movement direction detecting means.
A vehicle periphery monitoring device disclosed in Patent Document 2 includes a photographing means, an obstacle detecting means and a displaying means. The photographing means photographs a vehicle periphery including a portion of a self vehicle. The obstacle detecting means detects an obstacle located in the vehicle periphery and calculates a distance between the detected obstacle and the self vehicle. The displaying means displays, in a single monitoring screen, the photographed image photographed by the photographing means and an obstacle displaying image indicative of the distance calculated by the obstacle detecting means.